Do animals think? Do they experience joy, grief, even love? Do they laugh? These are some of the questions raised by Barbara J. King and Virginia Morell in their touching and provocative explorations of the latest research on animal minds and animal emotions. As Morell swiftly outlines in her introduction, the past three decades have witnessed a sea change regarding the kinds of questions that can be asked about animals and the kinds of language that can be used to describe them.

Animal research in the 20th century was dominated by the theories of Pavlov, who regarded all animal behaviors as conditioned, mechanical reactions and dismissed the very mention of animal emotions as anthropomorphism. Such views have increasingly given way to stories of animals as agents in their own right, and in these two books animals share the spotlight with their researchers as protagonists with their own special quirks and talents.

The change is significant for what it suggests about animal testing and research more generally. “It wasn’t a coincidence,” Morell notes, “that the use of animals in biomedical studies and pharmacological testing, and as industrially raised and hunted meat and fur products, grew exponentially while behaviorism flourished.” As Rene Descartes acknowledged in the 17th century, if animals are like machines, humans commit no crime in eating or killing them.

Both authors attribute many of the recent changes to Jane Goodall’s work with chimpanzees in the wild. Untrained in scientific protocol, Goodall attributed personalities and individual life histories to the chimps she studied and referred to as “she” or “he,” but not “it.” Goodall was convinced, moreover, that it was just a matter of time before observable evidence for animals having an inner, mental life would proliferate to the point where it could not be dismissed.

For Morell and King, that time is now, and it is easy to be convinced by their well-told and often heart-wrenching stories of monkeys clinging to dead infants, dolphins rescuing swimmers from sharks, a bird traveling 8,000 miles every season to mate with his injured and immobilized partner, or a 7-year-old elephant calf slowly stroking the remains of his dead mother’s skull. This last story appears in both books and is taken from an account by researchers Cynthia Moss and Karen McComb, who study elephants in the wild. Like the other stories, it’s compelling, but its status as evidence of grief is inconclusive. Follow-up research showed that elephants do prefer the bones of other elephants to those of different species but not that they recognize one elephant’s bones over another’s. (Ivory might offer a different story, McComb admits, but that has not been tested because of the importance of keeping ivory away from poachers.)

Partial to the kinds of stories they know lay readers enjoy, the authors also draw attention to the evidentiary weakness of anecdote and the need for repeatable experiments. Both writers are hopeful that, with increasing proof of the ways humans and animals share needs and emotions, animals will receive better protection in the lab and in the wild.

At the same time, the authors reveal how our quests for proof may themselves produce painful or disturbing experiences for animals. We see this in Morell’s early example of Nigel Franks, a scientist who has devoted much of his life to proving that individual ants make decisions to produce a colony. “Now you’ll see what these people do when their home is destroyed,” Frank said, upon ripping apart an ant nest in order to show how ants will reconstruct it in a new spot. Indeed, his work has brought him to describe ants as the “ first non-human animals to qualify as teachers,” and Morell looks on with him as ants patiently show their pupils how to locate landmarks that lead to their new nest. Destroying a home to prove a point is some way to treat a teacher!

Not only ants but rats, too, are excluded from the definition of “animal” and thus from laws demanding humane treatment by the Animal Welfare Act of 2004 — this despite our knowledge of rat sentience. In experiments conducted in the 1950s, rats were tossed into a vat of warm water to see if they would develop a “feeling of helplessness,” and they did give up the struggle, though whether because of feeling helpless, as the research suggested, or from sheer exhaustion is hard to tell. The cruelty of such research can be contrasted with more recent work. Jaak Panksepp, a pioneer in the new field of affective neuroscience, which explores “the zone where neurons, emotions, and cognition meet,” tickles rats to show that they like to laugh. It’s about play and “social joy,” he says, abilities that show evolutionary continuities of feeling across species.

Scientists have had a difficult time finding evidence of emotions in animals without deliberately provoking them, as Harry Harlow did in the 1930s. To demonstrate maternal attachment in monkeys, he raised baby macaques in isolation chambers, producing severely disturbed creatures. In more recent studies, evolution provides a framework for understanding the shared origins and status of emotions across species.

Darwin argued for such evolutionary continuity in his 1872 book, “Expression of the Emotions in Man and Animals,” and scientists continue to search for proof. An anthropologist by training, King goes to the field to look for behavioral changes following loss or separation. What is not clear, however, is whether she can tell the difference between the grief she observes in the wild and the pathological form that Harlow induced. Must we conclude that they are the same? And if not, how do we know and describe the difference that cause and context make?

Morell often turns to neuroscience to find evidence of distinct emotional states, but it seems to blur the differences. She reports, for example, that grief and panic have the same “neural network” in animals and in humans, such that the “feeling” of each is the same. Similarly, King suggests that emotions have nothing to do with cognition (and thus with cause or context), writing that grief is not “a feat of thinking” but of feeling. But can we separate feeling from cognition? If grief is a response to loss, doesn’t that also make it a sign of remembrance? Is this emphasis on feeling evidence of the authors’ hesitancy before the idea that animals might also think and distinguish loss from abuse? Have we returned to Pavlov?

It is, of course, safer to err by choosing a simple explanation for behavior — to say that the dog who, for 10 years after his owner’s death, returned day after day to meet him at the bus stop was acting merely out of habit, rather than a hope that his owner might one day return. We can’t ask the dog to tell us what he is thinking, but those of us who live with dogs are daily presented with evidence that they can think and choose and that they remember places, other dogs and other humans.

Thinking does not require language to affect how we feel. Language, however, may shape human emotions in ways that distinguish them from animal emotions, and this raises an important question that neither author addresses: whether a word like “grief” can rightly be used for both humans and animals. King points out that our words often help us escape our experiences, rather than face them as animals do. “Even if an animal could talk,” Morell asks, “would we listen?”Her point, and King’s too, is that they are in effect talking, although we humans may not always want to hear what they are saying. And when we do hear, I would ask, how faithful are our translations?

Kari Weilis university professor of letters at Wesleyan University and the author of “Thinking Animals: Why Animal Studies Now?”

HOW ANIMALS GRIEVE

By Barbara J. King

Univ. of Chicago. 193 pp. $25

ANIMAL WISE

The Thoughts and Emotions of Our Fellow Creatures

By Virginia Morell

Crown. 291 pp. $26

The books contain tales of monkeys clinging to dead infants, dolphins rescuing swimmers from sharks and a bird traveling 8,000 miles every season to mate with his injured and immobilized partner.

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